A known cable connector is disclosed in U.S. Pat. 4,602,831 and comprises, a housing block and an electrical cable having at least one signal wire connected to a corresponding signal contact on the housing block, and at least one reference wire of the cable for connection to a reference electrical potential. The signal wires transmit electrical signals, either electrical power or electrical encoded signals. The reference electrical potential is ground voltage. Along the cable a reference conductor shields the signal wires from undesired influence, such as electrostatic and electromagnetic coupling. In one form of cable, the reference conductor is a conductive shield that encircles a corresponding signal wire. A reference wire in contact with the shield connects to the connector and to a reference electrical potential present in the connector.
As the switching speeds of the signals become faster, there is a need for the signal contacts to become closer together, to shorten signal transmission paths between signal contacts, and to reduce an allocation of valuable space to be consumed by the contact spacing. The signal contacts are too close if they couple inductively and electrostatically, and produce cross talk and impedance mismatch.
As the switching speeds of the signals become faster, a further need exists to provide a low inductance return path in the connector, to control common impedance noise generation, and to establish coupling of each signal contact electromagnetically and electrostatically to the return path that is stronger than a similar coupling to other signal conductors, and to provide an impedance that matches the impedance of other parts of electrical circuits transmitting the signals, in order to reduce signal reflections. However, such a return path in the connector consumes additional space, and imposes a limit upon the closeness of the signal contacts. Thus a choice is presented, whether to eliminate a return path and risk undesired impedance mismatch and undesired coupling, or whether to provide adequate return paths and sacrifice valuable space to be consumed by increasing the contact spacing and by enlarging the connector.